Constructed: 324-448 CE

Emperor: Constantine I & Theodosius II

Use: Military Structure

The walls of Constantinople were the last great fortification system of antiquity. They were modified continuously over time but the major constructions were done by Constantine the Great in the 4th century, and Theodosius II in the 5th century. The walls wrap around the entire city. There were sea walls as well, which defended against naval assaults. They helped the Byzantine Empire defend Constantinople against countless sieges for about 1000 years.